$re = '/\,+(?![^\(]*\))/';
$str = 'WATER, CORN SYRUP AND 2% OR LESS OF EACH OF THE FOLLOWING: CONCENTRATED JUICES (ORANGE, TANGERINE, APPLE, LIME, GRAPEFRUIT), CITRIC ACID, MALIC ACID, ASCORBIC ACID (VITAMIN C), THIAMIN HYDROCHOLORIDE (VITAMIN B1), NATURAL FLAVORS. MODIFIED CORNSTARCH, CANOLA OIL, CELLULOSE GUM, SUCRALOSE, SODIUM HEXAMETAPHOSPHATE, POTASSIUM SORBATE TO PROTECT FLAVOR, YELLOW #5, YELLOW #6 AND DISODIUM EDTA TO PROTECT COLOR.';
preg_match_all($re, $str, $matches, PREG_SET_ORDER, 0);
// Print the entire match result
var_dump($matches);
Please keep in mind that these code samples are automatically generated and are not guaranteed to work. If you find any syntax errors, feel free to submit a bug report. For a full regex reference for PHP, please visit: http://php.net/manual/en/ref.pcre.php